The Insurance Institute for Business and Home Safety Research Center evaluates construction materials and systems in its state-of-the-art testing laboratories. Photos: Insurance Institute for Business and Home Safety.

Until early October of this past year, Chester County, South Carolina, was home to a small, single-story house, similar to thousands of houses across the United States, but unique in almost every way.

What made this small structure one of a kind? The house sat inside the large test chamber at the Insurance Institute for Business and Home Safety (IBHS) Research Center, dwarfed by the six-story chamber’s cavernous interior. The house was built, in fact, to be destroyed.

On Oct. 5, the staff of the IBHS Research Center focused the test chamber’s intense destructive wind power, generated by 105 super-sized fans, on the small structure. Prior to the test, the center had digitized the wind record of an actual storm, and the wind speeds produced by the fans were varied accordingly. In the case of the simulated storm in early October, wind speeds were increased in three phases, up to 120 miles an hour. The house experienced significant damage to its walls and interior, and the garage door was ripped off. But the roof, built to IBHS’ recommended standards, held firm.

The IBHS research facility, which opened in 2010 and is funded by property insurers, evaluates various residential and commercial construction materials and systems. The lab is the only lab in the world that can unleash the power of highly realistic windstorms, wind-driven rain, hailstorms and wildfire ember storms on full-scale one- and two-story residential and commercial buildings in a controlled, repeatable fashion.

The mission of IBHS is to reduce the social and economic effects of natural disasters. And much of its research, like its attack on this small house last October, has focused, at least in part, on the resilience of roofs. As IBHS President and CEO Julie Rochman has noted, “The roof is your first line of defense against anything Mother Nature inflicts … and during a bad storm your roof endures fierce pressure from wind, rain, and flying debris.”

Educating the Industry

In May of 2017, the EPDM Roofing Association (ERA) launched a microsite to help educate the construction industry about the increasing need for resilience in the built environment, and the contributions that EPDM roofing membrane can make to a

IBHS conducts hail research in the Laboratory Building for Small Tests, where hailstones of various sizes are recreated and propelled against roof samples. Photos: Insurance Institute for Business and Home Safety.

resilient system. That effort came in response to the increasing number of extreme weather events. Since last May when ERA first launched its resilience microsite, the pattern of extreme weather has continued unabated, in the form of wildfires throughout the west which were exacerbated by extreme heat, and Hurricanes Harvey and Irma which left devastating floods and wind damage in their wake.

For more than a decade, ERA leadership has supported research about factors that contribute to the resilience of EPDM as a membrane, and how it best functions in various roofing systems. More recently, ERA has invested in site-visits to leading research organizations that generate science-based data about resiliency in building systems, first to Oak Ridge National Laboratories, near Knoxville, Tennessee, and then to the National Research Energy Laboratories (NREL) in Golden, Colorado. Given the complementary goals of ERA and IBHS to help support the creation of truly resilient buildings, ERA leadership welcomed the opportunity to visit the South Carolina research facility.

Analyzing Hail Damage

The hail research at IBHS was of special interest to ERA, given ERA’s research that has consistently shown that EPDM membrane offers exceptionally strong resistance against hail damage. Based on field and test data sponsored by ERA, EPDM roof membranes outperform other roof systems in terms of hail protection. In 2007, ERA conducted tests which showed that EPDM roofing membranes did not suffer membrane damage and avoided leaking problems endemic to other roofing surfaces in similar circumstances. Of the 81 targets installed for that research over different surfaces, 76 did not fail when impacted with hail ice balls up to three inches in diameter. Perhaps most importantly, the impact resistance of both field-aged and heat-aged membranes in this test also clearly demonstrated that EPDM retains the bulk of its impact resistance as it ages.

The IBHS Research Center’s super-sized fans can recreate winds to measure their effects on full-scale one- and two-story residential and commercial buildings. Photos: Insurance Institute for Business and Home Safety.

Using this ERA-generated research as a starting point, ERA leadership travelled to IBHS with specific questions in mind, including: What has IBHS research revealed about the impact of hail on various types of roofing membranes and systems? Does the IBHS research reinforce or contradict ERA’s findings? What are the next questions to be asked about the damage that hail can do, and are resilient systems cost-effective?

Hail research at IBHS is conducted in the Laboratory Building for Small Tests, a compact structure with equipment appropriate to replicate large hailstones and hurl them at roof samples. As part of its research, IBHS has worked with the National Weather Service to assess the geographic locations threatened by hail. Individual storms have long been recognized as creating widespread and expensive destruction, but is hail a threat that is confined to just a few specific geographic areas of the country?

In fact, more than 75 percent of the cities in the United States experience at least one hailstorm a year, and the risk extends across the country to all areas east of the Rockies. Annually, hail losses reach more than 1 billion dollars. The IBHS has identified the factors that contribute to the extent of hailstorm damage, with the impact resistance of roofing materials being one of the most critical factors, along with hailstone size, density and hardness. Likewise, the roof is one of the components most vulnerable to hail. Analysis of property damage resulting from a hailstorm in Dallas-Fort Worth in 2011 found that roof losses accounted for 75 percent of property damage in the area, and more than 90 percent of damage payouts.

In their efforts to replicate the true nature of hail, the staff at IBHS has conducted extensive fieldwork, and travelled widely around the United States to gather actual hailstones immediately after a storm. Over the last five years, the IBHS hail team has collected more than 3,500 hailstones, focusing on their dimensions, mass and compressive stress. The stones range from .04 inches in diameter to well over four inches. In addition, IBHS has conducted three-D scans of more than one hundred stones to further educate themselves about the true nature of hailstones, and how they contribute to the overall damage inflicted by hailstorms.

The research findings of IBHS reinforce or complement those of ERA. IBHS has found that unsupported roofing materials perform poorly and ballasted low-slope roofs perform especially well in hailstorms because they disperse energy. IBHS recommends that builders use systems that have impact resistance approval, including their own fortified standard. While IBHS found that newer roofing membranes perform better than older membranes, ERA studies found that new, heat-aged and field-aged EPDM membranes all offered a high degree of hail resistance, demonstrating that EPDM retains the bulk of its impact resistance as it ages.

Both organizations stress that resilient roofing systems in new and retrofitted construction can make good financial sense. According to Julie Rochman of IBHS, “We are really going to continue focusing on moving our culture from one that is focused on post-disaster response and recovery to pre-disaster investment and loss-mitigation … we’re going to be very focused on getting the roofs right in this country.”

For the members of ERA, “getting the roof right” has long been a dominant focus of their businesses. Now, in the face of increasingly frequent and extreme weather events, getting the roof right means gathering up-to-the-minute research about resilient systems, and putting that research to work to create resilient roofs.

The effect of high winds on roofs is a complex phenomenon, and inadequate wind uplift design is a common factor in roofing failures. Damage from wind events has historically been dramatic, and wind-induced roof failure is one of the major contributors to insurance claims.

Roofing professionals have long recognized the importance of proper low-slope roof edge and gutter designs, particularly in high-wind conditions. For this reason, SPRI, the association representing sheet membrane and component suppliers to the commercial roofing industry, has spent more than a decade enhancing testing and design standards for these roofing details.

SPRI introduced the first version of its landmark standard, ANSI/SPRI/ES-1 “Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems” in 1998. Since then, the association has continually revised, re-designated and re-approved the document as an ANSI (American National Standards Institute) standard.

Testing of edge securement per ANSI/SPRI ES-1 is required per the International Building Code (IBC), which has been adopted by every state in the country.

This standard provides the basic requirements for wind-load resistance design and testing for roof-edge securement, perimeter edge systems, and nailers. It also provides minimum edge system material thicknesses that lead to satisfactory flatness, and designs to minimize corrosion.

Construction professionals have been successfully using the standard, along with the specifications and requirements of roofing membrane and edge system manufacturers to strengthen their wind designs.

Until recently, the biggest news on the wind design front was the approval of ANSI/SPRI/FM 4435/ES-1, “Wind Design Standard for Edge Systems Used with Low-slope Roofing Systems.” Let’s call it “4435/ES-1” for short. SPRI knew recent post-hurricane investigations by the Roofing Industry Committee on Weather Issues (RICOWI) and investigations of losses by FM Global consistently showed that, in many cases, damage to a low-slope roof system during high-wind events begins when the edge of the assembly becomes disengaged from the building. Once this occurs, the components of the roof system (membrane, insulation, etc.) are exposed. Damage then propagates across the entire roof system by peeling of the roof membrane, insulation, or a combination of the two.

Recognizing that edge metal is a leading cause of roof failures, SPRI has redoubled its efforts to create a series of new and revised documents for ANSI approval. As has always been the case, ANSI endorsement is a critical step toward the ultimate goal of getting these design criteria included in the IBC.

A Systems Approach to Enhancing Roof Edge Design

Roofing professionals understand that successful roof design requires the proper integration of a wide variety of roofing materials and components. For years, leading roofing manufacturers have taken a “systems” approach to their product lines. Recently, SPRI has zeroed in on the roof edge. Low-slope, metal perimeter edge details include fascia, coping and gutters, are critical systems that can strongly impact the long-term performance of single-ply roofs.

As part of the ES-1 testing protocol, RE-3 tests upward and outward simultaneous pull of a horizontal and vertical flanges of a parapet coping cap. Photo: OMG Edge Systems

SPRI first addressed roof gutters in 2010 with the development of ANSI/SPRI GD-1. The testing component of this document was recently separated out to create a test standard and a design standard. The test standard, GT-1, “Test Standard for Gutter Systems,” which was approved as an American National Standard on May 25, 2016.

Similarly, SPRI has revised 4435/ES-1 to only be a test standard.

Making both edge standards (4435/ES-1 and GT-1) into standalone testing documents makes it easier for designers, contractors and building code officials to reference the testing requirements needed for metal roof edge systems.

IBC requires that perimeter edge metal fascia and coping (excluding gutters), be tested per the three test methods, referred to as RE-1, RE-2 and RE-3 in the ES-1 standard. The design elements of ES-1 were never referenced in code, which caused some confusion as to how ES-1 was to be applied. The latest version of 4435/ES-1 (2017) only includes the tests referenced in code to eliminate that confusion.

Test methods in 4435/ES-1 2017 have the same names (RE-1, RE-2, and RE-3), and use the same test method as 4435/ES-1 2011. Because there are no changes to the test methods, any edge system tested to the 2011 version would not need to be retested using the 2017 version.

FM Global’s input was instrumental in the changes in 2011 when ANSI/SPRI ES-1 incorporated components of FM 4435 to become 4435/ES-1. However, there are no additional FM related changes in the latest 4435/ES-1 standard.

This gravel stop is being tested according to the ANSI/SPRI ES-1 standard using the RE-2 test for fascia systems. Photo: OMG Edge Systems

Per ANSI requirements, 4435/ES-1 2011 needed to be re-balloted, which is required by ANSI every five years. SPRI took this opportunity to have it approved as a test standard only to eliminate the confusion referenced above. FM Global was consulted and indicated it wanted to keep “FM” in the title. (FM was on the canvas list for the test standard and actually uses it as its own test standard.)

With 4435/ES-1 becoming a test standard for coping and fascia only, and GT-1 being a test standard for gutters, SPRI determined that a separate edge design standard was needed. Meet ED-1, a design standard for metal perimeter edge systems.

The design portions of the ES-1 edge and the GD-1 gutter standards have been combined and are now referenced by SPRI as ED-1. It has been developed and is currently being canvassed as an ANSI standard that will provide guidance for designing all perimeter edge metal including fascia, coping, and gutters.

ED-1 will be canvassed per the ANSI process later this year. However, SPRI is not planning to submit ED-1 for code approval.

SPRI ED-1 will include:

Material Design

Nailer attachment

Proper coverage

Recommended material thicknesses

Galvanic compatibility

Thermal movement

Testing requirements

“Appliance” attachment to edge systems

Limited Wind Design

Load to be required by the Authorities Having Jurisdiction (AHJ).

Tables similar to those included in 4435/ES-1 will be included for reference.

If this sounds a tad complex, imagine the design work required by the dedicated members of SPRI’s various subcommittees.

The Test Methods in Detail

The GT-1 standard is the newest, so let’s tackle this one first. As noted above, the ANSI/SPRI GT-1 test standard was developed by SPRI and received ANSI Approval in May of 2016. Testing of roof gutters is not currently required by IBC; however, field observations of numerous gutter failures in moderate to high winds, along with investigations by RICOWI following hurricanes have shown that improperly designed or installed gutters frequently fail in high wind events. GT-1 provides a test method that can be used by manufacturers of gutters, including contractors that brake or roll-form gutters, to determine if the gutter will resist wind design loads. Installing gutters tested to resist anticipated wind forces can give contractors peace of mind, and may provide a competitive advantage when presented to the building owner.

This gutter is being tested using the test method specified in ANSI/SPRI GD-1, “Design Standard for Gutter Systems Used with Low-Slope Roofs.” Photo: OMG Edge Systems

GT-1 tests full size and length samples (maximum 12 feet 0 inches) of gutter with brackets, straps, and fasteners installed per the gutter design. It is critical that the gutter be installed with the same brackets, straps, and fasteners, at the same spacing and locations as per the tested design to assure the gutter will perform in the field as tested. The fabricator should also label the gutter and/or provide documentation that the gutter system has been tested per GT-1 to resist the design loads required.

GT-1 consists primarily of three test methods (G-1, G-2, and G-3). Test method G-1 tests the resistance to wind loads acting outwardly on the face of the gutter, and G-2 tests the resistance to wind loads acting upwardly on the bottom of the gutter. G-3 tests resistance to the loads of ice and water acting downwardly on the bottom of the gutter.

Tests G-1 and G-2 are cycled (load, relax, increase load) tests to failure in both the original GD-1 standard and the new GT-1. The only change being that in GD-1 the loads are increased in increments of 10 lbf/ft2 (pound force per square foot) from 0 to failure, and in GT-1 they are increased in increments of 15 lbs/lf (pounds per linear foot) from 0 to 60 lbs/lf, then in 5 lbs/lf increments from above 60 lbs/lf to failure.

Note also that the units changed from lbf/ft2 (pound force per square foot) to lbs/lf (pounds per linear foot), which was done so that the tests could be run using the test apparatus loads without having to convert to pressures.

The GT-1 standard specifies a laboratory method for static testing external gutters. However, testing of gutters with a circular cross-section is not addressed in the standard, nor does the standard address water removal or the water-carrying capability of the gutter. In addition, downspouts and leaders are not included in the scope of the standard.

SPRI intends to submit ANSI/SPRI GT-1 for adoption in the next IBC code cycle.

As referenced above, IBC requires that perimeter edge metal (fascia and coping), excluding gutters, be tested per three test methods, referred to as RE-1, RE-2 and RE-3 in the ES-1 standard.

RE-1 tests the ability of the edge to secure a billowing membrane, and is only required for mechanically attached or ballasted membrane roof systems when there is no peel stop (seam plate or fasteners within 12 inches of the roof edge). RE-2 tests the outward pull for the horizontal face of an edge device. RE-3 tests upward and outward simultaneous pull on the horizontal and vertical sides of a parapet coping cap.

Calculating Roof Edge Design Pressures

All versions of ANSI/SPRI ES-1 and ANSI/SPRI GD-1, the 2011 version of ANSI/SPRI 4435/ES-1, and the new ED-1 standard all provide design information for calculating roof edge design pressures. These design calculations are based on ASCE7 (2005 and earlier), and consider the wind speed, building height, building exposure (terrain), and building use.

However, as stated above, IBC requires that the load calculation be per Chapter 16 of code, so the SPRI design standards are intended only as a reference for designers, fabricators, and installers of metal roof edge systems.

ES-1-tested edge metal is currently available from pre-manufactured suppliers, membrane manufacturers and metal fabricators that have tested their products at an approved laboratory.

The roofing contractor can also shop-fabricate edge metal, as long as the final product is tested by an approved testing service. The National Roofing Contractors Association (NRCA) has performed lab testing and maintains a certification listing for specific edge metal flashings using Intertek Testing Services, N.A. Visit www. nrca.net/rp/technical/details/files/its details.pdf for further details.

A list of shop fabricators that have obtained a sub-listing from NRCA to fabricate the tested edge metal products are also available at www. nrca.net/rp/technical/details/files/its details/authfab.aspx.

SPRI Continues to Take Lead Role in Wind Testing

As far back as 1998, SPRI broke ground with its ANSI/SPRI/ES-1 document addressing design and testing of low-slope perimeter edge metal. Today, the trade association has a variety of design documents at the roofing professional’s disposal, and is working to get ED-1 approved as an Edge Design Standard to be used for low-slope metal perimeter edge components that include fascia, coping and gutters.

Each time weather reports and news stories warn of impending heavy rains and hail, the Hail Investigation Program (HIP) Committee of the Roofing Industry Committee on Weather Issues (RICOWI) Inc., Clinton, Ohio, begins a process to determine whether the hail damage is sufficient to meet the HIP requirements for deployment of volunteer research teams.

Before the daily assignments began, the volunteers reviewed the various research requirements, met their team members and learned their responsibilities.

Mobilization criteria is met when “An event is identified as a hailstorm with hail stones greater than 1 1/2 inches in diameter causing significant damage covering an area of 5 square miles or more on one of the target- ed areas.” Once a storm that meets the criteria has been confirmed and meteorological data and local input have been obtained by HIP, a conference call with RICOWI’s Executive Committee is held to discuss HIP’s recommendation and review information. The Executive Committee decides whether to deploy.

On April 11, 2016, the hailstorm that damaged the Dallas/Fort Worth metroplex met the requirements for mobilization.

RESEARCH TEAMS AND BUILDINGS

Volunteer recruitment is an ongoing process throughout the year. RICOWI members are encouraged to volunteer as a deployment team member by completing forms online or at HIP committee meetings held twice a year in conjunction with RICOWI seminars and meetings.

Once a deployment is called, an email is sent to RICOWI members to alert the volunteers and encourage new volunteers. RICOWI sponsoring organizations also promote the investigation to their memberships. Volunteers are a mixture of new and returning personnel.

On May 2, 2016, 30 industry professionals traveled from across the U.S. to assemble in Texas. These volunteers were alerted to bring their trucks, ladders and safety equipment. To provide an impartial review, 10 teams of three volunteers were balanced with roofing material representatives, roofing consultants or engineers, meteorologists, contractors and researchers. Team members volunteered to be their team’s photographer, data collector or team leader.

When the deployment was called, press releases were sent to various media in the Dallas/Fort Worth area to alert local companies and homeowners of the research investigation. RICOWI staff began making calls immediately to the local area’s government officials to seek approval for the investigation teams to conduct research. Staff also made calls throughout the research week to help identify additional buildings.

A large area in and around Wylie, Texas, had hail as large as 4 inches in diameter.

Several methods are used to help determine which areas and roofs are chosen. A list of building permits were provided to RICOWI by local building officials to assist with roof choice. In addition, one of RICOWI’s members from the area did preliminary research and provided addresses for the teams. These site owners were contacted through phone and email to notify them of the research project.

Teams were assigned low- or steep- slope research and were assigned addresses accordingly. Team members carried copies of the press release and additional information to help introduce the investigation to business owners and homeowners.

Ultimately, the objective of the re- search project in Dallas/Fort Worth included the following:

Investigate the field performance of roofing assemblies after this major hail event.

Factually describe roof assembly performance and modes of damage.

Formally report the results for substantiated hail events.

DAY-TO-DAY DUTIES

Before the daily assignments began, the volunteers reviewed the various research requirements, met their team members and learned their responsibilities. The teams were briefed on safety, how to take proper photos and how to capture important data.

As each day began, a briefing was held providing assignments for the day. This included addresses for investigation based on whether the team was focused on low- or steep-slope research. The teams were encouraged to stop at other homes and facilities that were undergoing roof repairs in addition to their assigned inspections.

The days were hot and long for the teams. Volunteers began each day at 8 a.m. and many did not return until 5 or 6 p.m., depending on the number of roofs they were assigned. The temperature during the day was around 80 F and humid; the temperatures on the roofs were much worse.

NRCA has updated Roof Wind Designer, an online wind-load calculator intended to provide roofing professionals with an easy way to determine a roof system’s design wind loads for many commonly encountered building types subject to code compliance. Roof Wind Designer was developed in cooperation with the Midwest Roofing Contractors Association and North/East Roofing Contractors Association. The free Web-based application is based on ASCE 7, “Minimum Design Loads for Buildings and Other Structures”, 2005 and 2010 editions. Roof Wind Designer has also been updated to determine design wind loads applicable to perimeter edge-metal flashing system design, which helps compliance with ANSI/SPRI ES-1 requirements. The application is limited to building heights less than 60 feet and is applicable to roof systems with slopes up to 12:12 and hip roofs with slopes up to 6:12.

Two new federal government reports underscore not only the continued rapid growth of renewable energy sources (biomass, geothermal, hydropower, solar, wind) in the electric power sector but also the ongoing failure of government forecasts to accurately anticipate and predict that growth.

In the first 2016 issue of its monthly “Energy Infrastructure Update” report, the Federal Energy Regulatory Commission (FERC) notes that five new “units” of wind (468 megawatts) and 6 new units of solar (145 MW) accounted for 100 percent of new electrical generation brought into service in January. No new capacity for nuclear, coal, gas, or oil was reported. Renewables now account for 17.93 percent of total installed operating generating capacity in the U.S.: hydropower (8.56 percent), wind (6.37 percent), biomass (1.43 percent), solar (1.24 percent), and geothermal (0.33 percent). In fact, installed capacity for non-hydro renewables (biomass, geothermal, solar, wind) alone (9.37 percent) now exceeds that for either nuclear (9.15 percent) or oil (3.84 percent).

The new renewable energy capacity added in January is continuing a trend. Just a month earlier, FERC’s December 2015 “Energy Infrastructure Update” revealed that renewables had accounted for 64 percent of all new electrical generating capacity installed last year.

Separately, the U.S. Energy Information Administration (EIA) has issued its latest “Electric Power Monthly” (covering all twelve months of 2015) indicating that electricity generated by renewable energy sources grew by over 2 percent compared to 2014 and accounted for almost 13.5 percent of “utility-scale” electrical output in the U.S. last year.

Moreover, EIA’s end-of-the-year data reveals significantly higher growth in the renewable energy sector than the agency had forecast less than three months ago for calendar year 2015 in its “Short-Term Energy Outlook.” At that time, EIA said it expected “total renewables used in the electric power sector to decrease by 1.8 percent in 2015. Hydropower generation is forecast to decrease by 8.2 percent, and non-hydropower renewable power generation is forecast to increase by 4.2 percent.”

In reality, compared to calendar year 2014, non-hydro renewables increased by 6.9 percent, hydro output declined by just 3.2 percent, and the total of hydropower plus non-hydro renewables grew by 2.03 percent. For calendar year 2015, grid-scale renewables accounted for 13.44 percent of net U.S. electrical generation—up from 13.16 percent in 2014. Of that, non-hydro renewables accounted for 7.30 percent while conventional hydropower was 6.14 percent. Generation by all non-hydro renewable sources grew in 2015. Biomass was up by 0.3 percent, wind by 5.1 percent, geothermal by 5.6 percent, and solar by 49.6 percent.

Renewable energy growth is significantly outpacing earlier EIA projections. Less than four years ago, in its “Annual Energy Outlook 2012,” EIA forecast that non-hydro renewables would grow at an annual rate of 3.9 percent and provide about 250,000 thousand megawatt-hours in 2015 while non-hydro renewable electrical generating capacity would reach approximately 85 gigawatts (GW). It also forecast that non-hydro renewables would not surpass hydropower until 2020.

In fact, EIA now reports actual generation from non-hydro renewables in 2015 to have hit 298,358 thousand megawatt-hours from utility-scale facilities alone; in addition, at least 12,141 thousand megawatt-hours was provided by distributed solar photovoltaic and an unknown amount from other distributed, small-scale renewables that are not grid-connected (small wind). Further, electrical generation from non-hydro renewables surpassed that from hydropower more than a year ago.

And, according to FERC, the total installed generating capacity of wind, biomass, solar and geothermal units had reached 109.6 GW by January 2016—and this reflects just the combined capacity of larger renewable energy facilities. FERC’s data only includes plants with nameplate capacity of 1 MW or greater and therefore does not reflect the additional capacity provided by rooftop solar or other smaller, distributed renewable energy systems.

“Just a few years ago EIA had forecast that renewables might provide 15 percent of the nation’s electricity by 2035,” notes Ken Bossong, executive director of the SUN DAY Campaign. “It now appears that goal could be reached within the next two years and quite possibly sooner.”

The Roofing Industry Committee on Weather Issues (RICOWI), Clinton, Ohio, is committed to providing in-depth and comprehensive education to identify and address important technical issues related to the cause of wind and weather damage to roofing systems. RICOWI’s research and education initiatives focus on providing a broad knowledge base regarding wind, hail, energy efficiency and durability effects; establishing new/improved consensus standard practices for weather design and testing; and providing an educational platform of roof design and weather concepts within the building community.

RICOWI is currently seeking speakers for its 2016 Seminars. This is your opportunity to showcase your research, lessons learned in the field and educate others about the effects of weather on roofing systems.

How-to classes that stimulate and provide attendees with a new skill, technology or process.

Stimulating and cutting-edge for the construction and roofing industry.

Proposals for a better understanding of processes and techniques.

Solid research and data from case studies.

Upcoming research.

Presenters should have strong speaking experience and in-depth knowledge of subject matter presented. Topics should be related to the audience and not generic in nature and should not be product pitches.

Submission forms with abstracts should be submitted no later than June 15, 2015, to the RICOWI offices. The forms are available online. The RICOWI Conference and Education Committee will review, and authors will be notified regarding the selection of an abstract by Sept. 1, 2015. Once accepted, authors for the Spring 2016 seminar will be required to have bios and finalized abstracts in by Nov. 1, 2015, for the preliminary agenda publication on the RICOWI website and for distribution. All presentations and handouts will be due from presenters no later than Feb. 15, 2016.

I recently attended a continuing-education conference for civil/structural engineers that discussed changes in the 2012 International Building Code (IBC) and the referenced ASCE 7-10 “Minimum Design Loads for Buildings and Other Structures”. During the seminar, the question was asked: “Who is responsible for the design of wind loading to rooftop equipment as defined in the IBC and Chapter 29 of ASCE 7-10?” The most accepted response was to add a section in the structural general notes that wind design on rooftop equipment is to be designed “by others”.

A structural engineer designed the metal support system and load transfer from the newHVAC unit down through the structure.

The design requirements for wind loading on rooftop equipment have been included in previous editions of the IBC and ASCE 7, but significant changes have been included in ASCE 7-10. The increased attention is in part because of more severe wind events in recent years. While it is not the primary responsibility of the roofing consultant or contractor to evaluate the systems being placed on the roof, it is good to understand the code’s requirements for loading to rooftop equipment, how the load is determined and applied, and how the load is transferred to the building structure.

CODE REQUIREMENTS

The primary focus of the roofing professional in the IBC is concentrated on Chapter 15 (Roof Assemblies). While there are requirements in Chapter 15 addressing rooftop structures, these requirements, particularly in relation to wind loading, extend beyond Chapter 15. It is therefore imperative to be familiar with other sections of the code.

For instance, Section 1504 (Performance Requirements) refers the user multiple times to Chapter 16 (Structural Design) for wind-loading-design requirements. While roof manufacturers typically prequalify their systems based on various industry standards (ASTM, FM, ANSI, etc.), rooftop equipment supports are not typically prequalified because of the variability of placement and conditions. Similarly, new to this code cycle, Section 1509.7.1 includes the requirement for wind resistance for rooftop-mounted photovoltaic systems per Chapter 16 of the IBC. Other industries or trades have similar requirements. Section 301.15 of the 2012 International Mechanical Code and Section 301.10 of the 2012 Fuel and Gas Code require “equipment and supports that are exposed to wind shall be designed to resist the wind pressures in accordance with the IBC”.

Section 1609 of Chapter 16 (Wind Loads) applies to wind loading on every building or structure. Section 1609.1.1 provides two design options. The designer can use chapters 26 to 30 of ASCE 7-10 or Section 1609.6 of the IBC. Note however that Section 1609.6 is based on the design procedures used in Chapter 27 of ASCE 7-10, which does not address wind loading on rooftop equipment and thus is not applicable. Chapter 29 of ASCE 7-10 (Wind Loading on Other Structure and Building Appurtenances) contains the procedures used to determine wind loading on rooftop structures and equipment.

DETERMINING AND APPLYING WIND LOADING ON ROOFTOP EQUIPMENT

Properly specified ballasting blocks are designed and formed to better address the freeze/thaw cycle.

To determine wind loading on rooftop equipment, the first step is to identify the building Risk Category (formerly the Occupancy Category) and the building location. The Risk Category is determined from Section 1604.5 and Table 1604.5 of the IBC or Table 1.5-1 of ASCE 7-10. There are slight variations in the two codes but typically each will produce the same Risk Category.

The Risk Category and the location are then used to determine the design wind speed based on published wind-speed maps, available in Section 1609.3, figures 1609 A to C of the IBC, or Section 26.5.1, figures 26.5-1 A to C of ASCE 7-10. It can be difficult to read these maps to select the appropriate wind contour line, specifically along the East Coast. The Redwood City, Calif.-based Applied Technology Council (ATC), a non-profit that advances engineering applications for hazard mitigation, has digitized the maps providing a valuable resource for determining design wind speeds by GPS coordinates or the building’s address. Visit ATC’s wind-speed website. Note however that it is always advisable to cross check this design wind speed with the maps in the adopted code or with the local building authority.

The city of Moore, Okla., recognizes it cannot keep doing things the way they’ve always been done. You may recall on May 20, 2013, an EF5 tornado did extensive damage to the town. The new residential construction codes are based on research and damage evaluation by Chris Ramseyer and Lisa Holliday, civil engineers who were part of the National Science Foundation Rapid Response team that evaluated residential structural damage after the May 2013 tornado.

“A home is deconstructed by a tornado, starting with the breaching of the garage door,” Ramseyer explains. “The uplift generated by the wind causes the roof to collapse until the pressure pulls the building apart. These new residential building codes could possibly prevent that in the future.”

The new codes require roof sheathing, hurricane clips or framing anchors, continuous plywood bracing and windresistant garage doors. Moore’s new homes are required to withstand winds up to 135 mph rather than the standard 90 mph.

Although the city of Moore deserves to be commended for passing a more stringent building code less than one year after the 2013 tornado, this wasn’t the first damaging tornadic event Moore had experienced. The town also made national headlines in 1999 when it was hit by what was then considered the deadliest tornado since 1971. Moore also was damaged by tornadoes in 1998, 2003 and 2010. In my opinion, it was time for the Moore City Council to do the right thing by its citizens.

As extreme weather events occur more frequently, more emphasis is being placed on commercial roof wind resistance, as well. Robb Davis, P.E., recently attended a continuing-education conference for civil/structural engineers that discussed changes in the 2012 International Building Code and the referenced ASCE 7-10 “Minimum Design Loads for Buildings and Other Structures”. During the seminar, it became clear to Davis that nobody is specifically responsible for the design of wind loading to rooftop equipment as defined in the IBC and Chapter 29 of ASCE 7-10. Therefore, Davis reached out to Roofing because he believes it’s important roofing professionals understand the code requirements for wind loading to rooftop equipment, how the load is determined and applied, and how the load is transferred to the building structure. Davis shares his insight in “Tech Point”.

As Davis points out in his article, by better understanding wind loads on rooftop equipment, roofing professionals will be even better positioned to lead the design and construction industry in creating more resilient roofs and, ultimately, strengthening the structure and protecting the people underneath.

Liberated Energy Inc. has released the Guard-Lite, a revolutionary hybrid lighting and security system. Its unique self-powered design enables it to be installed at any location without wiring or an electrical permit. With an increasing need for security and the demand for alternative energy growing, the Guard Lite provides a complete solution.

A wireless solar and wind powered construction camera fills a void in remote areas where security and surveillance couldn’t be performed before because of the costly expense in trying to provide power and an Internet connection to those areas. Liberated Energy makes this void a thing of the past by offering a cellular construction camera that is indefinitely powered by a solar panel and wind turbine and controlled by a web-based User Interface. Visit the topics below and see how a Liberated Energy Guard Lite can help your construction business:

Zip-UP Ceiling finishing system is designed for finishing the underside of exterior soffits at schools, hospitals, airports, and commercial facilities. Testing for wind pressure, under both static load and cyclic load, was performed in accordance with the requirements of the Florida Building Code (High Velocity Hurricane Zone) and the product meets every Florida standard for static and cyclic load tests of hurricane strength winds. The Static Load Test (TAS 202) is performed, in several ascending stages, under test conditions that eventually meet -110 psf design pressure for a prescribed length of time. The Cyclic Load Test (TAS 203) tests under various alternating positive/negative pressures for 631 cycles.

Made from durable interlocking PVC components engineered to fit together easily, Zip-UP Ceiling provides a flat, clean, grid-free washable mildew and mold resistant paintable ceiling surface. The panels unzip for quick access to mechanical and electrical services in the soffit. Unlike steel finishing systems which rust and require pressure washing, Zip-UP Ceiling is rust-free and can be cleaned with a garden hose.

The manufacturer warrants that the system is free from defects, materials and workmanship for 25 years from the date of purchase and that the components will continue to zip together for that time.

Sponsored Messages

@roofingmag on Twitter

March/April 2019

Read our latest issue in digital format.

About Roofing

Roofing is a national publication that unravels, investigates and analyzes how to properly design, install and maintain a roof system. Through the voices of professionals in the field, Roofing’s editorial provides a unique perspective.